A new detection method of 99Tc by nuclear excitation

A new nuclear excitation process, 99Tc(γ,γ')99mTc reaction, was applied for the first time to radioactivation analysis of technetium. Bremsstrahlung irradiation of 99Tc samples gave the reaction product 99mTc which emits γ-ray easily measurable by a semiconductor detector. The production rate of 99mTc per μg 99Tc was linearly correlated with the flux of bremsstrahlung. The detection limit of 99Tc was estimated to be nanogram order (0.63 Bq 99Tc) under the optimum irradiation condition. Possible interference by 100Ru(γ, p)99mTc reaction was also studied, which could be discriminated from the (γ,γ') reaction by simultaneously occurring 98Ru(γ,p)97Ru reaction. (author) 17 refs.; 7 figs